I'm also following this thread with great interest. Good job so far! But just thought I'd add, I've worked with epoxy a great deal (I use marine-grade West System epoxy - it has great wet-out properties but definitely isn't cheap at about 3x the price of polyester). It's a little more flexible than polyester (more flexibility means you can use less glass without your piece being as prone to breaking), but I've not had any problems with it not being rigid enough for most models made with cardstock paper to hold their shape, and I've done some really huge pep models too which held up pretty well once the outer coat was cured too. It just takes a good 3-4 days for epoxy to cure to maximum strength, and during that time, you need to ensure your pep model has enough support that it doesn't collapse or bend out of shape during the wait, or it will finish curing and stay that way. On the upside though, virtually no noxious fumes, and the surface of cured epoxy resin doesn't stay tacky like it tends to for polyester resin (well, it's a plus if you're not looking to do multiple layups). If you used a decent epoxy (I'm not sure what type you bought, but it doesn't sound like it was marine grade), that's the likeliest reason why the polyester didn't stick to it very well - polyester's adhesion properties aren't as good as epoxy's, and because epoxy's surface cures smooth and tack free, you would have to sand it with low-grit paper to give your model a much rougher surface for the polyester to adhere to, so it's better to simply not mix them.
